Spectroscopic Two-dimensional Observation of Flames in an Industrial Furnace for Steel Processing

Abstract

In this study, a spectroscopic method is applied to measure two-dimensional (2D) distributions of flame temperatures during regenerative combustion of natural gas with highly preheated air in a test furnace of industrial size. By using a CCD camera fitted with an optical bandpass filter, the 2D distributions of the continuum emission from soot particles in premix and diffusion flames are measured at two different wavelengths. Subsequently, the temperature is determined on the basis of the two-color 2D thermometry, in which the ratio of the 2D emission intensity distributions is converted into the 2D temperature distribution with much higher spatial resolution in comparison with those obtainable by thermocouples. The emission profiles of NO radiation also were measured and the results are discussed in conjunction with difference in the temperature profiles of the flames.